Glucocorticoids (GCs) have been used for decades to treat acute and chronic inflammatory and immune conditions, including rheumatoid arthritis, asthma, chronic obstructive pulmonary disease (“COPD”), osteoarthritis, rheumatic fever, allergic rhinitis, systemic lupus erythematosus, Crohn's disease, inflammatory bowel disease, and ulcerative colitis. Examples of GCs include dexamethasone, prednisone, and prednisolone. Unfortunately, GCs are often associated with severe and sometimes irreversible side effects, such as osteoporosis, hyperglycemia, effects on glucose metabolism (diabetes mellitus), skin thinning, hypertension, glaucoma, muscle atrophy, Cushing's syndrome, fluid homeostasis, and psychosis (depression). These side effects can particularly limit the use of GCs in a chronic setting. Thus, a need continues to exist for alternative therapies that possess the beneficial effects of GCs, but with a reduced likelihood of side effects.
GCs form a complex with the GC receptor (GR) to regulate gene transcription. The GC-GR complex translocates to the cell nucleus, and then binds to GC response elements (GREs) in the promoter regions of various genes. The resulting GC-GR-GRE complex, in turn, activates or inhibits transcription of proximally located genes. The GC-GR complex also (or alternatively) may negatively regulate gene transcription by a process that does not involve DNA binding. In this process, termed transrepression, the GC-GR complex enters the nucleus and directly interacts (via protein-protein interaction) with other transcription factors, repressing their ability to induce gene transcription and thus protein expression.
Some of the side effects of GCs are believed to be the result of cross-reactivity with other steroid receptors (e.g., progesterone, androgen, mineralocorticoid, and estrogen receptors), which have somewhat homologous ligand binding domains; and/or the inability to selectively modulate gene expression and downstream signaling. Consequently, it is believed that an efficacious selective GR modulator (SGRM), which binds to GR with greater affinity relative to other steroid hormone receptors, would provide an alternative therapy to address the unmet need for a therapy that possesses the beneficial effects of GCs, while, at the same time, having fewer side effects.
A range of compounds have been reported to have SGRM activity. See, e.g., WO2007/0467747, WO2007/114763, WO2008/006627, WO2008/055709, WO2008/055710, WO2008/052808, WO2008/063116, WO2008/076048, WO2008/079073, WO2008/098798, WO2009/065503, WO2009/142569, WO2009/142571, WO2010/009814, WO2013/001294, and EP2072509. Still, there continues to be a need for new SGRMs that exhibit, for example, an improved potency, efficacy, effectiveness in steroid-insensitive patients, selectivity, solubility allowing for oral administration, pharmacokinetic profile allowing for a desirable dosing regimen, stability on the shelf (e.g., hydrolytic, thermal, chemical, or photochemical stability), crystallinity, tolerability for a range of patients, side effect profile and/or safety profile.